Applications of organic photochemistry to natural product synthesis are being explored. Photocyclizations of N-allyliminium salts which occur by electron transfer mechanisms are being employed in the construction of members of the harringtonine alkaloid family. As part of these efforts, we are also developing new and synthetically use ful electron transfer initiated photochemical processes. For example new methods for photoarylation are under investigation and will be used in the synthesis of the cephalotaxine structure. Additional studies directed at the development of general methods for quinoline and isoquinoline alkaloid synthesis are underway. The natural product series selected as targets for the synthetic work contain chemotherapeutically active substances.